VENTILATION CONDITIONS AND THE RELATED SYMPTOMS IN SELECTED INDOOR ENVIRONMENTS IN A UNIVERSITY

Limited data are available for understanding indoor environmental quality (IEQ) and the related health effects in schools in China. This paper reports the air exchange rates (AERs) of 50 rooms in a university in Tianjin, China, and explores the relationship between ventilation conditions and symptoms. All of the 50 rooms were visited during June to August, 2006, including 20 dormitories and 5 reading rooms using ceiling fans, 10 old classrooms with split air-conditioners in an old building and 10 new classrooms with air circulation cooling system in a new building, and 5 conference rooms with split air-conditioners. Temperature, relative humidity (RH), and CO2 concentrations were continuously monitored for 12h in each room, and out of the building simultaneously. Occupants in the rooms, all being undergraduates, were investigated by questionnaires regarding time-activity patterns, judgment about IAE in campus and comfortlessness possibly relative to bad ventilation. Room characteristics, ventilation methods and numbers of occupants and their activities were also recorded. AERs were derived from CO2 concentration decay curves obtained when rooms were unoccupied. CO2 concentration, temperature and RH ranged 615~5346 ppm, 18.9~39ºC and 30~90%, respectively. Average AERs were 1.2, 1.9, 1.6, 1.1 and 0.7 hr-1 in dormitories, reading rooms, old classrooms, new classrooms and conference rooms, respectively. In dormitories, factors such as outdoor climate conditions, deficiency of building design, room usage and living habits of students, were considered to be essential on ventilation and indoor CO2 concentration. More complaints and symptoms were found in dormitories, classrooms and conference rooms, whose AERs were lowest. CO2 concentrations was highly associated with symptoms such as absence of mind, fidget and headache, regardless of the comfortable temperature (22~28℃) and RH (40~70%) range. In dormitories, AER or CO2 concentrations was not a key factor influencing comfort, instead, students' judgments on IEQ depended on RH and temperature.